The scientific nature of the mind-body problem

Pedro Fonseca

I – The present mind-body
problem

1. Nowadays we stumble across a conceptual difficulty in explaining
everything that is related with consciousness. We do not understand why it has appeared in natural evolution
and how it is caused by merely
physical entities. We do not understand why it was (and is) necessary to
improve animal behaviour because it adds nothing to the behaviour of any
physical being (the behaviour would be exactly the same if it only possessed
physical properties – if it was an automaton or a zombie). And we do not understand
how they are possible because we do normally admit (upon scientific reflection)
that what there is, the fabric of the world, is just a set of elementary
physical particles (EPP), that makes up everything else. The logical consequence of this ontological
commitment is that non-elementary entities are just representations,
tools, introduced in explanations. They are certainly useful to us – given our
very limited powers of calculation and measurement – but are nevertheless mere
images of what in reality is just an
incommensurable jumble of EPP.Through
this perspective, it seems impossible to ascribe any role to consciousness, or
to conjecture how it arises from matter. In reality, everything would be
simpler if we did not exist (phenomenologically).

2. But can or should we change the assumption that
EPP are sufficient to have a complete description of reality? I think that we
should because I believe that, as long as we do not change this assumption, we
will not be able to explain consciousness. For suppose that the behaviour of
any physical entity can indeed be completely predicted, even if only in
principle, employing exclusively a complete description of the physical
properties of EPP.[1]One
of the consequences is that non-EPP cannot possess causal powers, and,
following Occam’s principle, they should not, therefore, exist. The reason for
this is simple: the introduction of entities that do not have causal relations
with other entities can only be made arbitrarily (since the attribution,
non-attribution or misattribution of ‘green’ to a physical system has no
consequences, how should we choose between them?). So, we may think that,
following the opposite direction, i.e. considering as evidence the causal
properties of the mind, and proceeding to the appropriate adjustments to the
actual assumptions, theories or interpretations of science, we should head, in
a better way, to a new scientific paradigm, simultaneously less mysterious and
more believable, one which we might, luckily, achieve. We are therefore
assuming that our best scientific theories should be consistent with a possible solution to the mind-body
problem. In this way, not only philosophical discussions, should highly rely on
the concepts of physics, but the scientific theories should also try to be
consistent with every area of what we can experience.

3. The difficulty in pursuing this research avenue
(besides the fact that almost no one is following it) is that any description,
which attributes causal powers to entities that are not EPP, seems to enter the
domain of superstition or irrationality. There are at least two problems
regarding the view that non-EPP entities may have causal powers. First, it
might be argued that a non-EPP entity with causal powers is a contradiction in
terms. But it can also be argued that the problem of explaining consciousness
would not be helped by the addition of non-EPP entities with causal properties
– consciousness would remain as mysterious as ever. Let’s start by the first
argument. In general it is simply assumed that almost every property of a
composite is determined by the properties of its (elementary) parts. So it is
said that two objects indistinguishable at the level of their parts could not
have different (intrinsic) properties. This claim is made stronger if we
consider a 4-dimensional region of space-time so that the EPP will include, not
only a particular moment of the world, but a part (or the all) of its history.

But imagine, by the contrary, that the parts of
an object would be insufficient, somehow, to describe its causal powers. This
is what happens in (at least) some quantum events. We have a description of the
elementary parts of an object (like a radioactive atom) or even of an
elementary object (like a photon). But this description involves a substantial
degree of uncertainty. We know that an atom has a certain probability of
decaying, but will it decay? Neither the theory, nor further observations seem
able to answer that question. Some people have argued that reality ceases to be
objective at the quantum level, that perhaps the future is not completely
determined by the past and so on. This is speculative, but it is sufficient to
show not only the conceivability but the actual possibility of having two
exactly alike atoms, even in twin universes, and seeing one of them decaying
while the other does not decay.

Let’s consider this sufficient to assert that exactly
the same composites may behave in different ways (not only as a logical but
also as a real possibility). Would this help solving the problem of
consciousness? We would still have to secure two different caveats. First , if
consciousness has some causal powers, then it must have not only the
opportunity to show them, but it must actually show them. What we see in
quantum systems like electrons, etc, is just random behaviour. This is not what
we would expect to happen in the brain. If we ever find that there are quantum
random mechanisms in the brain we should expect to find that they, contrary to
the current predictions of our current physical theories, do not operate
randomly – consciousness should show itself in the world in an unambiguous
manner, it should have strong empirical consequences. The second caveat is that
we must separate the problem of finding a place or function for consciousness,
or choice, in the natural world, from the problem of providing a reductive
explanation of consciousness. Even if we were to discover that the person is
behaving in a way not explainable by physical theory we could still believe
(perhaps even more!) that everything we were living was just a dream or an
illusion placed in us by some Cartesian demon. The possibility that everyone
around us is nothing but a zombie is as real as the possibility that the world
is nothing but an illusion. These are sceptical doubts that are beyond the
frontiers of our knowledge, and I cannot imagine how anyone (or even a being
like God) could escape these doubts unless by simple acceptance or faith.

4. In spite – or perhaps because – of these
changes inside the physical paradigm, almost all solutions to the mind-body
problem have searched for a conceptual disentanglement that do not contemplate
physics. The solutions were searched and found in the lines of interpreting
current physics as if it were Newtonian physics: idealism, parallelism or
physicalism are just interpretations of Newtonian physics. But these
interpretations cannot avoid the problem that stems from Newtonian physical
theory: consciousness has no place or function in nature.[2]

The actual incapacity of achieving a consensual
explanation by any of these solutions corroborates our hypothesis according to
which, without taking into account some major step back from the deterministic
worldview endorsed to us by Newtonian physics, the problem is simply intractable.

5. Today we can witness some efforts to take
advantage of certain assumptions in contemporary physics that may reveal to
make the mind-body problem tractable. Penrose and Hameroff have been part of
the few that havestrived to
accommodate quantum physics and neurology (assuming small arrangements in both)
with the existence of the mind. In a more radical effort, the empirical
investigations leaded (which do not address directly the problem of the mind)
by Prigogine seem to suggest that the impossibility of predicting the behaviour
of unstable systems is not due to a lack of information but to the intrinsic
nature of the system. If this is true, a certain solution to the mind-body
problem would be possible: since the elementary description is not sufficient
to completely predict the behaviour of the system, other non-elementary
(physical) properties might be not causally irrelevant – a solution that could,
at least in part, suit a Bergsonian solution to the mind-body problem.[3]

One of the main differences between Penrose and
Prigogine’s solution is that the first depends in an essential way of the not
well-understood quantum effect of superposition. In the second, it will perhaps
be possible to imagine a conscious system (with physical causation) based in an
unstable system (with no quantum superposition states). Another line of
investigation is to connect Leibniz parallelism with Everett’s interpretation
of quantum mechanics. This project, however, presents several remarkable
difficulties, the main one is the repugnant but apparently unavoidable
conclusion that almost everyone we know are nothing but automatons (although we
would not be able to distinguish between automatons and real persons).

II - Argument

To clarify the argument let’s present it in a
more schematic way. Basically it consists of three premises and two syllogisms.

Premises

The first, “A”, is a definition of what I call
the classical mind-body problem, of which a special case is treated by Kant,
Leibniz, etc, and can also be found to have an important weight in arguments
provided by Putnam, Papineau, Dennett, etc. I suppose “B” and “C” are accepted facts.

A

The mind-body problem can be understood as a consequence from the
thesis that minds cannot have causal (physical) powers due to the nature of the
world (and not by reflection on inner experiences, or metaphysical
assumptions). It arises in every complex system in which behaviour is
predictable through a complete description of its elementary parts. That is, it
is generated in every system of entities arranged in such a way that, if
composite entities exist, their behaviour is considered to be determined solely
by the behaviour of the elementary parts that constitute them and their
surrounding. It is unimportant if these elementary particles are considered
physical (whatever this means) or not: a simple epistemological consideration
will suffice to show that (from the previous assumption) the relation between
parts and composites is sufficient to preclude any non-arbitrary assignment
(from an non-pragmatic point of view) of causal efficacy to composites of any
degree of complexity (even those formed only by two elementary particles).[4]

B

Newtonian dynamics was thought to provide such
a system of the world. Since every particle behaviour and concatenation of
particles was thought to be predictable (in principle) with absolute certainty.
(It is very difficult to say if Newtonian dynamics did really said this,
especially because it is still impossible to solve equations were involved in
predicting the behaviour of several particles at a time: the classical example
is the three-body problem.)

C

Quantum mechanics does not provide such a
world-view. The equations do not allow us to predict accurate observations in
most cases. This is all we need. Nevertheless it may be unsatisfying not
to get a world-view corresponding to indeterministic particle behaviour. Several
interpretations are possible but we must remember they are only
interpretations, in the sense that they have a relevant and non-eliminable
level of arbitrariness. However, since this may provide a more intuitive perspective
to our argument, we may say, for instance, that the equations do not describe
what we see but only the mechanisms that lead to possible observations. We
could reframe this by saying that quantum mechanics equations describe
possibilities, or the state of possible affairs. These possibilities have,
nevertheless our intuitions about matter, a causal role. If we redefine our
intuitions on matter such as to include the causal efficacy of possibilities we
will end up with a conception of matter that does not operate at a mechanical level.
Most important for our discussions, if possibilities define what happen they
can never yield exact observational results because the mathematical result
consists in a set of possibilities, from which only through actual experiment,
some emerge as real. Observation, not theory, decides between possibilities,
and this means they are intrinsically unpredictable. Anyway, we can use other
interpretations of quantum mechanics, including Everett’s, for us the result is
the same: no predictability.

Syllogisms

The situation in the seventeenth century could
be defined as:

B

B à A

\ A

With the evolution of predictive mathematical
models it was paradoxically found that predictions have a maximum degree of
accuracy. Newtonian dynamics was replaced but quantum mechanics mathematical
models do not support A. It remains to be seen if they imply ~A.

correct argument

C

C Ú A

\ ??

but sometimes

C

B à A

\ A (fallacy)

III - Relevance

I don’t think the main argument can be easily
considered wrong. It’s too simple for that, and its premises are almost all
trivial. The main criticism (which may turn out to be true, but only to some
extent) is that it is irrelevant. I can thing of at least two reasons may be
given for this. What I’ll call a weak and a strong one.

Weak: just to say that it does not solve the ‘hard
problem’ of consciousness (the ‘zombie problem’) and a host of related
problems. For instance, problems related to the search of the neural correlates
of consciousness. I would like to say that this is not a criticism, just a
clarification, but it nevertheless shows that it is important to distinguish
between general sceptical problems and problems amenable to scientific
discourse.. I am not very sure that, after we solve the scientific problems, (mind-body
problem included), many things remain to be solved. Part of my conviction
resides in the fact that at least some of these problems consist in perennial
philosophical problems (that does not happen in what we called the mind-body
problem). Finding a solution to these kind of questions, like knowing if the
world is real, or if we were created just five minutes ago with all memories
implanted inside, or if the sun will rise tomorrow, etc, seem therefore much
more improbable. Perhaps we will find that there is no answer to these problems
except simple allegiance.

Strong: The scary part is that the mind-body problem
can perhaps be re-established at another level of reality. For instance, at the
molecular or biological level. My answer here is weaker than the former: if at
all possible the re-establishment of the mind-body problem at a higher level
cannot be derived from quantum mechanics, the equations do not tell us when
particles begin to behave like good disciplined corpuscles. To have good
reasons to believe in such orderly behaviour from a certain level up in
relevant organisms (like brains) we would need evidence that cannot be derived
from the general outlook that quantum mechanics gives us of the way the world
works. That is, we would need to show, by other kind of empirical evidence,
that these relevant organisms, or all of its parts at a single level, behave in
a predictable way. For instance, if we would find that all molecules behave in
a predictable way than it would seem that brains would also have to be
considered as behaving predictably. In any case the resulting world-view would
be rather strange, having a closure of chemistry or biology but considering at
the same time physics to be incomplete. Even if this criticism turns out to be
sound, it does demand quite a revolution in our current picture of the world.

Notes:

[1] I take this to be roughly equivalent to the thesis of the causal
closure of the physical. And the fact that quantum mechanics does not allow, in
some hidden-variables interpretations, a complete
description of elementary particles does not affect our argument since, besides
EPP (and with the exception, according with the Copenhagen Interpretation, of
the mysterious interactions with the (conscious) device that makes the
observation) no other entities are considered relevant to make predictions.

[2] Notice that, when physics first appeared, it was understood as
‘natural philosophy’. It should deal with a part of the world (a very delimited
part of the world) while the rest of philosophy would take care of the rest.
But nowadays we understand much better that the claims of science are not only
valid for the skies or for inanimate objects. The problem is that, in extending
the claims of physics in such a way as to encompass the behaviour on all living
beings, of every conscious experience, we must also demand that physics must be
judged on the solution of problems that it never even tried to address before
(like the problem of consciousness). We should demand that physics, now that it
tries to explain what fundaments our phenomenal experience, must itself change to
accommodate the phenomenal experience which it tries to have a hold on
explaining. This is necessary, for the evolution of science.

[3] “Life [or consciousness], therefore, must be something which avails itself of a certain elasticity in
matter – slight in amount as this probably is – and turns it to the profit of liberty by stealing into whatever
infinitesimal fraction of indetermination that inert matter may present.”
H. Bergson, “Life and Consciousness” p.18.

[4] There is also a relation here, not yet very
clear to the problem of individuation, but we will skip that part here.